6c58d3827c
Completes the F7 family (Volatility) end to end: - Rust core: natr.rs (ATR as a percentage of close), std_dev.rs (rolling population standard deviation), ulcer_index.rs (RMS of trailing-high drawdowns — downside-only risk), historical_volatility.rs (annualised sample stddev of log returns). Each with a full Indicator impl, runnable doctest and reference / constant-series / warmup / reset / batch==streaming tests. - Python: PyNatr / PyStdDev / PyUlcerIndex / PyHistoricalVolatility PyO3 classes + module registration + .pyi stubs. - Node: StdDevNode / UlcerIndexNode via the scalar macro, explicit NatrNode and HistoricalVolatilityNode; index.d.ts and index.js updated. - WASM: WasmStdDev / WasmUlcerIndex / WasmHistoricalVolatility via the scalar macro, explicit WasmNatr. - Wiki: Indicator-Natr/StdDev/UlcerIndex/HistoricalVolatility.md plus rows in Indicators-Overview.md and entries in Home.md. cargo fmt + clippy (core/wickra/data/wasm/node) clean; 350 core tests, 25 data tests and 49 doctests green.